Depend on slint directly in the Android app

android_main takes an AndroidApp and calls slint::android::init, both of
which come from slint itself rather than from dr-ui. The backend feature
still arrives through dr-ui's target-specific dependency. anyhow was unused.

Assisted-by: LLM

Cargo.lock

@@ -1158,9 +1158,9 @@ name = "darkroom-android"
 version = "0.1.0"
 dependencies = [
  "android_logger",
- "anyhow",
  "dr-ui",
  "log",
+ "slint",
 ]
 
 [[package]]